Mechanical forces and fields at the nano/microscale shape the way cells interact and respond to the environment, and are central to a broad range of physiological functions. The cellular response to topographic and mechanical cues is fundamentally different in diseases such as metastatic cancer, due to the resultant alterations to the cascade of biochemical signals. Exploring the mechano-chemical coupling can not only reveal the progression profile of a disease state, but also shed light on its mechanistic underpinnings facilitating the development of new therapeutic regimen. Yet, gaining insights into the nanomechanical-biochemical interactions has proven to be challenging, owing to the lack of non-invasive experimental tools with the requisite mechanical deformation, spatial resolution and molecular sensitivity attributes. The goal of this New Innovator proposal is to address this unmet need by developing a unified, non-invasive platform that provides simultaneous nanometric deformation and real-time measurement of structural and biochemical responses in live functioning cells. Leveraging a novel nanofabrication strategy, we propose to engineer plasmonic vertical nanopillar arrays that enable mechanical loading for adherent cells while also providing ultrasensitive, molecular-specific and highly localized plasmon-enhanced Raman spectroscopy measurements. These salient features offer a unique portal for label-free investigation of the biochemical milieu with sub-diffraction-limit spatial resolution owing to the confined nature of the plasmonic field at the nanopillar tip. We will use this label-free platform to probe latent mechano-chemical coupling events prevalent in cell progression, and to establish biophysical and molecular markers characterizing malignant transformation. Specifically, we plan to decode the architectural control of mechanotransduction in ephrin A1-induced Ephrin A receptor 2 (EPHA2) reorganization, which represents a vital cell communication event with implications for cancer growth and metastasis. Furthermore, we will dissect organ-specific differences in isogenic metastatic breast cancer cells by establishing objective phenotypic differences and monitor cellular responses under the influence of FDA-approved drugs. Together, this will offer fresh insights into druggable targets and inform better therapeutic options tailored for the management and ablation of treatment-resistant metastatic lesions. Overall, this study will not only offer a fresh, innovative approach towards understanding cellular recognition of topographic and mechanical cues at the nanoscale but will also create the foundation for a diagnostic and therapy response monitoring platform through quantitative, stain-free and orthogonal cytological evaluation.